Structures and electronic properties of platinum nitride by density functional theory

We present the results of ground state electronic structure calculations of the zinc-blende and rocksalt phases of binary platinum nitride (PtN) using density functional theory. Several exchange-correlation functionals including the local spin density approximations, generalized gradient approximations (GGA), a nonempirical meta-GGA, and a screened Coulomb hybrid functional have been employed. We use Gaussian type orbitals within the framework of periodic boundary conditions. Our results confirm earlier findings, in that the zinc-blende structure of PtN is energetically more stable than the rocksalt structure. The predicted energy difference between the two phases is rather small with the more elaborate functionals. Both phases are predicted to be metallic and extended Pt d-N p hybridizations are found in both of them. We have also calculated the phase transition pressure between both phases. The bulk modulus of the zinc-blend phase of PtN is significantly higher than that of bulk platinum.